Assessment of groundwater potential zones and mapping using GIS/RS techniques and analytic hierarchy process: A case study on saline soil area, Nakhon Ratchasima, Thailand

The research purpose is to assess and delineate groundwater potential zones (GWPZs) in the saline soil area in the districts of Non-Thai, Non-Sung, Non-Daeng, Khong, and Kham Sakae Saeng, Nakhon Ratchasima province, Thailand, using remote sensing (RS), geographical information system (GIS), and analytical hierarchy process (AHP) techniques. The GWPZs were created by combining multiple influencing factors such as slope, landforms, annual rainfall, soil texture class, drainage density, geology, hydrogeological unit, land use/land cover, groundwater potential, and normalized difference vegetation index of the study area. The AHP technique was used to determine the weights of various thematic layers to identify the groundwater potential zone. The weights of the thematic layers in descending order consisted of hydrogeological unit (17.61%), geology (17.10%), groundwater potential (12.09%), soil texture class (12.09%), drainage density (8.55%), landforms (8.46%), land use/land cover (6.05%), slope (6.01%), annual rainfall (6.01%), and normalized difference vegetation index (6.01%), respectively. The acceptable consistency ratio (CR) is used to evaluate the reliability of AHP techniques, and which coefficient of determination (R²) of 0.7131 was used to validate the salinity data of 17 groundwater wells. The overall weightage of the AHP technique assessment was classified into 5 categories of the GWPZs including very high potential, high potential, moderate potential, poor potential, and very poor potential. The mostly groundwater quality distribution represented a moderate potential of about 1,101 km² (46.01%) to a poor potential of about 1,114 km² (46.57%) from the 2,390 km² of the study area located throughout the study area especially Kham Sakae Saeng, Non-Thai, and Non-Sung districts.